The second Polish tank appearing (the first one being TKS tankette earlier).

It is the tier IV Czołg średni B.B.T.Br.Panc (Czołg średni meaning medium tank). The project was developed in Poland under the designation 25TP in January 1937. One of the variants was proposed by the Technical Research Bureau of Armored Weaponry (BBT Br. Panc.) under the guidance of major R. Gundlach. Prior to the outbreak of WWII, a wooden model was built, but afterwards all work was discontinued.